Bio-fiber reinforced high-density polyethylene composites - A sustainable approach to improve flame retardancy, biodegradation, and water resistance

This study presents a sustainable strategy to enhance the multifunctional properties of high-density polyethylene (HDPE) by reinforcing it with sugarcane bagasse fibers (BFs) at varying weight ratios. The developed bio-composites aim to address critical limitations of conventional HDPE, particularly in flame retardancy, environmental persistence, and moisture sensitivity, there by expanding its applicability in eco-conscious packaging, agriculture, and construction sectors. The composites were thoroughly characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) to examine interfacial bonding and fiber dispersion, respectively. Mechanical testing revealed a marked enhancement in tensile strength (from 90 kg/cm 2 in neat HDPE to 234 kg/cm 2 in the HDPE10/90BFs composite), alongside a rise in Shore D hardness (from 65 to 90), with a concurrent decrease in elongation at break, indicating a trade-off between rigidity and ductility. Thermal analysis via TGA demonstrated a significant increase in char residue and thermal stability at elevated temperatures. Fire performance was substantially improved, with the limiting oxygen index (LOI) rising from 17 to 32.5. Furthermore, toxic gas emissions during combustion were mitigated, as evidenced by reduced CO (from 0.019 to 0.011 ppm) and CO 2 (from 2.082 to 0.645ppm) levels. Crucially, the composites exhibited enhanced environmental responsiveness, with water uptake decreasing and biodegradability increasing proportionally with BFs content reaching up to 46% weight loss after 14 days compared to only 10.18% in neat HDPE. These findings demonstrate that BFs-reinforced HDPE composites not only retain structural integrity but also provide significant environmental and safety advantages.